Nanotechnology has been heralded as the next major technological leap, in that it is prophesied to yield a variety of substantial advantages in terms of material characteristics, including electronic, optical and structural characteristics. Some have predicted that advances in nanotechnology are the best hope for extending the lifespan of Moore's law.
While nanotechnology advances have produced materials with myriad interesting properties with broad potential applicability, the integration of these materials into useful devices, systems and materials has remained somewhat of a stumbling block when viewed from the perspective of commercial manufacturability. By way of example, carbon nanotubes, often viewed as the hallmark of nanomaterials, are largely unusable from a commercial standpoint as anything more than filler for composite materials, e.g., to impart structural, and perhaps crude electrical properties to the overall bulk composite. This is because these nanotubes often have unpredictable electrical properties from one nanotube to the next, requiring a sensitive selection process in order to be able to use them reproducibly for more exacting requirements, e.g., in electronics, etc.
Another difficulty that affects virtually all nanomaterials is the integration of these materials into devices and/or systems where placement of such materials is important, e.g., bridging electrical contacts, spanning gate electrodes, etc. In particular, these materials are so small that it is virtually impossible to accurately position them using manual manipulative techniques, particularly from a commercial manufacturing standpoint, e.g., in large quantities with high yields. A number of methods have been proposed and demonstrated for positioning of these materials using more manageable methods. For example, flow directed placement methods have been successfully utilized to direct and place semiconductor nanowires in desired locations, e.g., where solutions containing wires or nanotubes are flowed into contact with substrates to both align, via the flow, and place, via the contact regions, wires onto the substrate surface. Molecular recognition and self assembly techniques, e.g., using chemical groups on the desired locations of the substrates and complementary groups on the nanomaterials, have also been proposed and demonstrated for the placement of nanomaterials in desired locations of substrates. Despite the reported effectiveness of these methods in positioning nanomaterials, to date such methods have yielded widely disparate results, e.g., in the uniformity of the deposition, orientation and positioning of the materials. The lack of uniformity is very detrimental in a commercial manufacturing setting, particularly when applied to, e.g., the electronics industry where product to product variations must be virtually non-existent. These methods also suffer from manufacturing requirements that will require substantial infrastructure development as well as development of an “art” form in the performance of these techniques.
Accordingly, there exists a need for a robust, repeatable process for the positioning and/or orientation of nanomaterials on other substrate materials for use in, e.g., electronics, optoelectronic, optical and material applications. The present invention meets these and a variety of other needs.